Paddle-style medical lead and method

ABSTRACT

A medical lead for electrical stimulation or sensing. The medical lead has a generally flat paddle on the distal end of the lead body. An electrode array is provided on the paddle, with the electrode array displaced along the length of the paddle toward the distal end. Advantages include allowing the electrode array may be advanced into position for electrical stimulation or sensing with the flat paddle extending through connective tissue, such as the ligamentum flavum, thus facilitating repositioning, withdrawal or explanting the medical lead, as well as using the flat features of the paddle to anchor the lead to the connective tissue.

RELATED APPLICATIONS

This application claims priority to provisional U.S. Application Ser.No. 60/420,570, filed Oct. 23, 2002, and provisional U.S. ApplicationSer. No. 60/508,107, filed Oct. 2, 2003.

FIELD OF THE INVENTION

This application relates generally to medical leads for electricalstimulation or sensing and methods of use thereof, and more particularlyto a paddle-style lead, for example, for spinal cord stimulation andmethods of use thereof.

BACKGROUND OF THE INVENTION

Currently anesthesiologists may non-surgically implant a percutaneousversions of medical leads for spinal cord stimulation (SCS) with Touhyneedles. Typically, percutaneous versions of medical leads have beenvarious standard cylindrical styles rather than flattened paddle styleleads, which tend to be surgically implanted by surgeons with theassociated discomfort, expense and inconvenience of surgical procedures.Paddle-style leads, however, are at least perceived to be more stable intheir location after implantation.

U.S. Pat. No. 6,309,401 and EP Publication No. 1 048 270 discloses anapparatus for percutaneous implant of a paddle style lead in which aneedle having a flattened cross section is used. U.S. Pat. No. 6,309,401and EP 1 048 270 are incorporated herein by reference in their entirety,and particular note is made of the flattened needle, which may be usedwith certain exemplary embodiments of the medical lead disclosed herein.

There is a well-known need or desire for a paddle-style lead that can beimplanted without performing a surgical procedure, such as a laminectomyor laminotomy.

SUMMARY OF EXEMPLARY EMBODIMENTS OF THE INVENTION

A medical lead is provided for electrical stimulation or sensing.Exemplary embodiments of the medical lead are adapted to facilitaterepositioning, withdrawal or explanting the medical lead, as well asusing the features of a flat lead paddle to anchor the lead to theconnective tissue. Exemplary embodiments of the medical lead are adaptedfor percutaneous introduction of the medical lead through an introducerneedle, such as a flattened Tuohy needle.

An exemplary medical lead has a generally flat paddle on the distal endof the lead body. An electrode array is provided on the paddle, with theelectrode array displaced along the length of the paddle toward thedistal end. The length of the paddle between the electrode array andproximal end of the paddle allow the electrode array may be advancedinto position for electrical stimulation or sensing with a proximalportion of the flat paddle extending through connective tissue, such asthe ligamentum flavum. Because the edge formed by the proximal end ofthe paddle is not pushed through the connective tissue, it does notinterfere with repositioning, withdrawing or explanting the medicallead. In addition, the flat features of the paddle may be used to anchorthe lead to the connective tissue.

A first exemplary embodiment of the medical lead comprises a generallyround or tubular lead body having proximal and distal ends, and at leastone electrical conductor extending between the proximal and distal ends.A connector is provided on the proximal end of the lead body inelectrical communication with the electrical conductor. A generally flatpaddle on the distal end of the lead body has an electrode arraycomprising at least one electrode in electrical communication with theelectrical conductor. The paddle has proximal and distal ends and alength extending between the proximal and distal ends. The electrodearray is displaced along the length of the paddle toward the distal end,whereby the electrode array may be advanced into position for electricalstimulation or sensing with the flat paddle extending through connectivetissue, such as the ligamentum flavum.

A second exemplary embodiment of the medical lead generally comprises agenerally round or tubular lead body having proximal and distal ends,and at least one electrical conductor extending between the proximal anddistal ends. A connector is provided on the proximal end of the leadbody in electrical communication with the electrical conductor. Agenerally flat paddle on the distal end of the lead body has anelectrode array comprising at least one electrode in electricalcommunication with the electrical conductor. The paddle has proximal anddistal ends and a length extending between the proximal and distal ends.The electrode array is displaced along the length of the paddle towardthe distal end such that the portion of the flat paddle proximal of theelectrode array has a length of at least 1½ inches (40 mm).

In an exemplary aspect of the first and second exemplary embodiments, amedical lead system is provided comprising the medical lead and ananchor adapted for clamping the flat paddle and anchoring it toconnective tissue, such as the ligamentum flavum. For example, theanchor may comprise two clamping jaws adapted to clamp the majorsurfaces of the flat paddle therebetween. One of the clamping arms mayoptionally be provided with at least one rib, e.g., a plurality such asthree ribs, adapted to engage the flat paddle and retain it in position.The clamping arms may be designed to be separable, with the clampingarms being provided with mating knobs and cavities or other features forattaching the clamping arms together.

A third exemplary embodiment is a medical lead system that generallycomprises a medical lead and an anchor. The medical lead comprises agenerally round or tubular lead body having proximal and distal ends,and at least one electrical conductor extending between the proximal anddistal ends. A connector is provided on the proximal end of the leadbody in electrical communication with the electrical conductor. Agenerally flat paddle on the distal end of the lead body has anelectrode array comprising at least one electrode in electricalcommunication with the electrical conductor. The paddle has proximal anddistal ends and a length extending between the proximal and distal ends,with the electrode array optionally being displaced along the length ofthe paddle toward the distal end. The anchor is configured forattachment to the paddle to anchor the paddle relative to biologicaltissue.

In a fourth exemplary embodiment, a method generally comprisespercutaneously introducing distal end of the paddle with an introducerneedle generally through connective tissue, such as the ligamentumflavum, into or adjacent a desired stimulation or sensing site, such asepidural space for spinal cord stimulation, in a patient with theproximal end of the paddle left extending out from the connectivetissue. The flat paddle may be anchored to the connective tissue. Thepaddle may be repositioned or removed without cutting through ordissecting the connective tissue (e.g., ligamentum flavum).

In an exemplary embodiment of an implantation method, a medical lead isused having a generally flat paddle having proximal and distal ends anda length extending between the proximal and distal ends, and anelectrode array comprising at least one electrode, with the electrodearray being displaced along the length of the paddle toward the distalend. The method of this exemplary embodiment generally comprises (a)percutaneously introducing distal end of the paddle generally anteriorlythrough the ligamentum flavum into an epidural space of a patientthrough a needle with the proximal end of the paddle remaining on theposterior side of the ligamentum flavum; and anchoring the paddle to theposterior side of the ligamentum flavum.

An additional exemplary embodiment includes a medical lead having anidentification marker for determining orientation or identifying thelead. For example, the marker may provide a definite indication of thedirection of the lead (which way it is facing), and/or be coded toidentify the model or serial number of a lead.

In yet another exemplary embodiment of a medical lead, the leadgenerally comprises a generally flat paddle on the distal end of thelead body. The paddle has first and second major surfaces, and anelectrode array comprising at least one electrode in electricalcommunication with the electrical conductor, the electrode array havingdirectional electrical field properties relative to the first and majorsurfaces of the paddle. An orientation marker is provided fordetermining orientation of the lead, the orientation marking includingfluoroscopically viewable material.

In still another exemplary embodiment of a medical lead, the leadgenerally comprises a lead body having proximal and distal ends, and atleast one electrical conductor extending between the proximal and distalends. A connector is on the proximal end of the lead body in electricalcommunication with the electrical conductor. A generally flat paddle isprovided on the distal end of the lead body. The paddle has proximal anddistal ends, first and second major surfaces, and a length extendingbetween the proximal and distal ends. An electrode array is provided onthe paddle comprising at least one electrode in electrical communicationwith the electrical conductor, the electrode array having directionalelectrical field properties relative to the first and second majorsurfaces. An orientation marker is provided for determining orientationof the lead. The orientation marking includes fluoroscopically viewablematerial.

Yet another exemplary embodiment is a combination or set comprising apaddle-style medical lead and a flattened needle. Preferably thecombination further includes a plastic or elastomeric stylet that iscable of being withdrawn from the needle even if the needle has beensubjected to plastic deformation.

Still another exemplary embodiment is a system comprising a medical leadand an implantable pulse generator. The system preferably includes atleast one or two external programmer(s), such a physician programmer anda patient programmer.

These and other features are described hereinafter or in the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an exemplary embodiment of a systemincluding a medical lead, implantable pulse generator (IPG) andprogrammer.

FIG. 2 illustrates various anatomical features of a portion of thevertebral column, including connective tissue, such as the ligamentumflavum through which medical leads are passed into the epidural spacefor electrical stimulation or sensing of the nerves of the spinal cord.

FIG. 3 is a cross sectional view along a transverse plane of a vertebralcolumn.

FIG. 4 is a plan view of an exemplary paddle-style medical lead of theinvention.

FIG. 5 is a plan view the paddle of FIG. 4.

FIG. 6 is a partial view of a second exemplary embodiment of thepaddle-style lead, illustrating among other things an orientationmarker.

FIG. 7 is an enlarged view of a portion of the exemplary medical lead ofFIG. 6, illustrating features of an exemplary electrode and paddle.

FIG. 8 is an exploded, partial view of the exemplary paddle-stylemedical lead of FIGS. 6 and 7.

FIG. 9 is an exploded, partial view of the exemplary paddle-stylemedical lead of FIGS. 6-8, illustrating the location of a butt jointjoining the paddle with the lead body.

FIG. 10 is a perspective view of an exemplary center strut, which is oneof two alternative preferred exemplary structures for use in the leadbody of the medical lead of FIGS. 6-9.

FIG. 11 is a cross sectional view of the exemplary center strut of FIG.10, illustrating aspects of a center strut.

FIG. 12 is a perspective view of an exemplary pentalumen tubing, whichis the other of two alternative preferred exemplary structures for usein the lead body of the medical lead of FIGS. 6-9.

FIG. 13 is a cross sectional view of the exemplary pentalumen tubing ofFIG. 12, illustrating illustrating aspects of pentalumen tubing.

FIG. 14 is a perspective view of an exemplary embodiment of an electrodeand crimp tube for electrically connecting a conductor wire with theelectrode.

FIG. 15 is an end view of the electrode and crimp tube of FIG. 8.

FIG. 16 is a back view of a second exemplary embodiment of an electrodewith an integral crimp feature for connecting a conductor wire with theelectrode.

FIG. 17 is an end view of the exemplary electrode of FIG. 16.

FIG. 18 is a perspective view of a half portion of an exemplaryembodiment of the paddle, illustrating the connection of a conductorwire to the electrode via a crimp tube arranged along a lateral side ofthe electrode, the arrangement being such that tension tends to turn theelectrode thus providing some additional strain relief.

FIG. 19 is a perspective view of two half portions of an exemplaryembodiment of the paddle, illustrating aspects of assembly of thepaddle.

FIG. 20 is a perspective view of the paddle with one half portionremoved to illustrate passage of a stylet.

FIG. 21 is a perspective view of an exemplary embodiment of a conductorand crimp sleeve for use in connecting to a proximal contact.

FIG. 22 is a perspective view of an exemplary embodiment of a conductorand crimp sleeve of FIG. 13 shown in relation with an exemplary proximalcontact.

FIG. 23 is a perspective view of a second exemplary embodiment of acrimp sleeve for use in connecting a conductor to a proximal contact.

FIG. 24 is a perspective view of a second exemplary embodiment of aproximal contact for use with the exemplary crimp sleeve of FIG. 23.

FIGS. 25 and 26 are perspective views of an exemplary embodiments of aproximal area of a lead and the interface between the lead body and leadpaddle, illustrating location of adhesive to minimize tensile loading ofelectrical conductors, contacts and electrodes.

FIG. 27 is a perspective view illustrating an exemplary embodiment ofthe assembly of a proximal contact on an exemplary embodiment of acenter strut of a lead.

FIG. 28 is a perspective view illustrating electrically conductiveproximal contacts separated by electrically insulative spacers.

FIG. 29 is a perspective view illustrating electrically conductiveproximal contacts separated by electrically insulative spacers arrangedon pentalumen tubing.

FIG. 30-33 are perspective views of an exemplary embodiment of an anchorfor use with exemplary embodiments of the medical lead.

FIGS. 34 and 35 are perspective views of additional exemplaryembodiments of an anchor for use with exemplary embodiments of themedical lead.

FIG. 36 is a perspective view of an exemplary embodiment of a needle,which has a flattened or oblong cross section for insertion of exemplaryembodiments of the medical lead.

FIG. 37 is a vertical cross section view along a sagittal planeillustrating use of the needle of FIG. 36 to place a lead epidurally.

FIG. 38 is a perspective view illustrating an exemplary embodiment of astylet for use in the oblong needle of FIGS. 36 and 37.

FIG. 39 is a flow chart illustrating an exemplary embodiment of a methodof percutaneously implanting a medical lead.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

FIG. 1 is a schematic view of a patient 10 having an implant of aneurological stimulation system employing the present invention tostimulate spinal cord 12 of the patient. The preferred system employsimplantable pulse generator (IPG) 14 to produce a number of independentstimulation pulses which are sent to spinal cord 12 by insulated lead 16and coupled to the spinal cord by electrodes located at point 18. Anextension, which includes a conductor, may also be used to electricallyconnect the IPG to the lead 16.

Implantable pulse generator 14 may be, for example, a neurostimulator,such as the neurostimulators available under the trade designations“Model 7425 Itrel™ 3 Neurostimulator” or “Model 7427 Synergy™Neurostimulator,” both available from Medtronic, Inc., Minneapolis,Minn. Exemplary embodiments of such implantable pulse generators 14typically include a battery or other power source, a processor, and aconnector header for connection of a lead or lead extension to the IPG,as well as a telemetry antenna to allow communication with the IPG to orfrom an external device.

This exemplary system may employ a programmer 20, which is coupled viaconductor 22 to radio frequency antenna 24. This permits attendingmedical personnel to select the various pulse output options afterimplant using radio frequency communications. While the exemplary systememploys fully implanted elements, systems employing partially implantedgenerators and radio-frequency coupling may also practice the presentinvention. The system may also include a patient programmer (similar atthe schematic level to the programmer 20) allowing the patient to selector modify the stimulation therapy program.

While the preferred exemplary system employs fully implanted elements,systems employing partially implanted generators and radio-frequencycoupling may also be used (e.g., similar to products sold by Medtronic,Inc. under the trademarks X-trel and Mattrix).

FIGS. 2 and 3 illustrate details of spinal or vertebral anatomy,including connective tissue, such as the ligamentum flavum 30 (FIG. 2)and the posterior epidural space 32 (FIG. 3). Exemplary embodiments ofthe medical lead 50 are adapted to be implanted through the ligamentumflavum 30 into the epidural space 32 into position for electrical spinalcord stimulation. FIG. 2 also illustrates, among other things, theanterior longitudinal ligament 33, intertransverse ligament 34,interspinal ligament 35, and supraspinal ligament 36, and, of course,vertebra 37. FIG. 3 also illustrates, among other things, the spinalcord 38, intrethecal space 39, and anterior epidural space 40.

FIGS. 4-8 show two exemplary embodiments of the paddle-style lead 50.The medical lead 50 comprises a generally round or tubular lead body 52having proximal and distal ends 54 and 56, and at least one electricalconductor 58 (e.g., 4 or 8) extending between the proximal and distalends. A connector or contact ring 60 is provided on the proximal end 54of the lead body 52 in electrical communication with the electricalconductor 58. A generally flat paddle 62 is provided on the distal end56 of the lead body 52.

An electrode array 64 is provided on the flat paddle 62 comprising atleast one electrode 66 (e.g., four or eight electrodes) in electricalcommunication with the electrical conductor 58 (e.g., four or eightconductors corresponding to the number of electrodes). The paddle 62 hasproximal and distal ends 68 and 70 and a length “L_(O)” extendingbetween the proximal and distal ends. The electrode array 64 isdisplaced along the length of the paddle toward the distal end 70. Forexample, the portion of the flat paddle proximal of the electrode arrayhas a length L_(P) of at least 4 inches (100 mm), 3 inches (75 mm), 2inches (50 mm) or 1½ inches (40 mm).

In one preferred exemplary embodiment, four conductors are provided witheach comprising fluoropolymer insulated 0.005 diameter MP35N—Ag corecables. Four connectors or contact rings 58 may be configured toconstitute, for example, an in-line cylindrical connector system forconnection to a lead extension or IPG. Four electrodes may also beprovided each comprising platinum/iridium. Such exemplary embodimentsmay have a total lead length of 25 cm to 100 cm, e.g., 30, 45 and 60 cmstandardized lengths. Of course, other dimensions, materials and numberof electrodes could be employed, and these are provided for purposes ofillustration only.

One exemplary paddle 62 may have a nominal length of 8 inches (20 cm),nominal width of 0.15 inches (3.8 mm), and a nominal thickness of 0.04inches (1 mm). The paddle 62 may be formed, for example, of materialincluding polyurethane, and in one exemplary embodiment is formed ofgenerally transparent polyurethane material

The proximal end 68 of the flat paddle 62 preferably tapers down to thediameter of the lead body 52 as illustrated in FIGS. 4, 5, 6 and 8. FIG.9 illustrates the butt joint 69 that may be used between the paddle 62and the lead body 52. The butt bond 69 may be formed, for example, withurethane adhesive.

The electrodes 66 may be recessed relative to the surface of the paddleas illustrated in FIG. 7, or co-planer with the surface. Examplesinclude recessing the electrode 0.010 inches (0.25 mm) from the surfacewith the electrode having a surface area of approximately 6 mm².

An identification or orientation marker 67 (FIGS. 6 and 8) may beprovided on the paddle 62 to indicate to physicians which side of theelectrode plate is exposed versus insulated during and after implant.This may be helpful, for example, to determine whether the lead 50 hasflipped or twisted during implantation. For example, an orientationmarker 67 for determining orientation of the lead 50 may includefluoroscopically viewable material, such as radio-opaque material (e.g.,platinum or platinum/iridium alloy). Since the electrode array 64 of atleast one exemplary embodiment of medical lead comprises electrodes 66exposed only through the first major surface of the paddle 62, theorientation marker 67 may be employed to provide a definite indicationof the direction the paddle 62 (and electrode array 64) is facing.

For example, the paddle 62 may be considered as defining an imaginarylongitudinal center line, and the orientation marker 67 may comprise adiscrete radio-opaque marker 63 displaced from the longitudinal centerline. When fluoroscopically viewing an implanted medical lead, theorientation of the paddle 62 may be determined by noting on which sideof the imaginary center line the orientation marker 67 appears to bepositioned.

In an exemplary embodiment, the orientation marker may compriseradio-opaque material arranged in an asymmetric manner with respect tothe width of the paddle. As an alternative example of this embodiment,the orientation marker may comprise radio-opaque material dispersed inthe paddle in an asymmetric manner with respect to the width of thepaddle. Such radio-opaque material may be dispersed, for example,substantially uniformly in an asymmetric portion arranged asymmetricallywith respect to the width of the paddle. The orientation of theimplanted paddle may be determined by viewing an apparent asymmetricposition of the orientation marker on the paddle, and determining, basedon the apparent asymmetric position of the orientation marker, whichdirection the paddle is facing.

In a preferred exemplary embodiment, the orientation marker 67 is codedto identify the model or serial number of the lead 50. The code wouldpreferably be fluoroscopically visible after implantation of the lead50.

Exemplary embodiments of the lead body 52 preferably includes a centerstrut 53 as illustrated in FIGS. 10 and 11, or pentalumen tubing 55 asillustrated FIGS. 12 and 13. The exemplary center strut defines acentral stylet lumen and longitudinally extending channels for receivingconductor wires. The exemplary pentalumn tubing defiens a central styletlumen and a plurality (e.g., 4) of longitudinally extending conductorlumens arranged radially outwardly from the central stylet lumen.

FIGS. 14-17 illustrate alternative preferred exemplary embodiments ofmeans for electrically connecting a conductor wire to the electrode. Theexemplary embodiment of FIGS. 14 and 15 involve use of a connector 70(e.g., crimp tube 70), which is crimped to the conductor and welded,e.g., laser welded) to the lateral edge of the electrode 66. Theexemplary embodiment of FIGS. 16 and 17 involves a crimp connector 71that is an integral part of the electrode 72. The crimp connector 71 isshown in the form of a tab (also 71) that may be bent or crimped toconnect the conductor to the electrode 72.

The exemplary embodiments of the connection means illustrated in FIGS.14-17 are adapted to have strain or tension relief properties if theconductors are put under tension. Each of these means are illustrated asconnecting the conductor to the lateral edge of the electrode 66 or 72(relative to the longitudinal centerline of the paddle) such thattension along the conductor would tend to spin the electrode 66 or 72thus tending to relieve such tension.

The paddle 62 may be formed of two half sections 74 and 76 (e.g.,“lower” paddle half 74 and “upper” paddle half 76) as shown on FIGS.18-20. For example, the half sections 70 and 72 may be formed ofpolyurethane. Electrode receiving apertures 78 may be provided (e.g.,molded) in the lower paddle half 74. Conductor wire paths 80 andstylet-lumen-forming channels 82 may be formed (e.g., molded) in one ofboth of the lower and upper paddle halves 74 and 76.

The sections 74 and 76 are bonded together (e.g., with polyurethaneadhesive) after assembly and connection (e.g., laser welding and/orcrimping) of the electrodes 66 and conductors. The stylet-lumen formingchannels 82 thus form a stylet lumen.

FIGS. 21 and 22 illustrate aspects of an exemplary embodiment of a crimpsleeve 84 for electrically connecting the proximal contacts 86 (e.g.,contact ring) and conductor wires 88. A miniature conductor 88 iscrimped to the sleeve 84, and the proximal contact 86 includes a slot 90for receiving the crimp sleeve 84. In at least one example, the sleeve84 is then bent and its end flattened to match the slot 90 in thecontact 86, and the crimped cable/sleeve assembly is welded to thecontact 86.

FIGS. 23 and 24 illustrate aspects of a second preferred exemplaryembodiment of a crimp sleeve 92 and proximal contact ring 94. Thecontact ring 94 is generally cylindrical and has a longitudinal slot 96for receiving the flared contact-connecting portion 98 of the crimpsleeve 92, which may be welded, for example, in place. The crimp sleeveincludes a conductor-wire-receiving channel 99, which may be crimped toretain the conductor wire. Exemplary alternatives to the channel 99include without limitation a crimp-able lumen (not shown).

FIG. 25 illustrates an example of where (e.g., at 100) the center strut53 may be adhesively bonded to the proximal end of the paddle 62 (e.g.,with urethane adhesive). FIG. 27 illustrates the distal end 56 of thebody portion 52, which is bonded to the proximal end of the paddle at100 in FIG. 25.

FIGS. 27-29 illustrate various exemplary details of the proximal contactportion and the assembly thereof. For example, FIG. 27 illustratesassembly of proximal contacts 92 on a center strut 53 alternating withassembly of an electrically insulative urethane spacer 102. FIG. 29illustrates an exemplary arrangement of proximal contacts 92 andurethane spacer 102 arranged on a pentalumen tube 55.

An anchor, such as the anchor 104 illustrated in FIGS. 30-33, may beprovided for clamping the flat paddle 62 and anchoring it to connectivetissue, such as the ligamentum flavum 30. For example, two clamping jaws106 and 107 of the anchor 104 are adapted to clamp the major surfaces ofthe flat paddle 62. One or both of the clamping arms 106 or 107 may beprovided with at least one rib, but preferably a plurality of ribs 108(e.g., 3), adapted to engage the flat paddle 62 and retain it inposition. Suture loops 110 may be provided to suture the anchor 104 toconnective tissue. The clamping arms 106 and 107 are preferablyseparable, with the clamping arms 106 and 107 being provided with matingknobs 112 and cavities 114 or other features for attaching the clampingarms 106 and 107 together.

FIGS. 34 and 35 illustrate alternative exemplary embodiments of ananchor 116 in which the halves or jaws 118 and 119 pivot relative to oneanother in a clam shell fashion to anchor the lead 50. This embodimentmay employ mating knobs and ribs as discussed with respect to theembodiment of FIGS. 30-33.

FIGS. 36-38 illustrate a preferred embodiment of a needle 200 and stylet202 for use in exemplary embodiments of a procedure for introducing apaddle style lead 50 within the spinal column area, such as the epiduralarea, as depicted in FIG. 37. Alternative exemplary embodiments may intoor near other nervous system structures, central or peripheral, such asintracranial nervous system structures or peripheral nerves.

As illustrated in FIG. 37, the needle assembly may be inserted into thespinal column area (e.g., epidurally). In an exemplary embodiment of theneedle assembly, the lumen of the needle 200 has an oblong cross sectionsized to insert a paddle style lead 50 and has a curve at the distal endof the needle 200. U.S. Pat. Nos. 6,249,707 and 6,309,401, and EP 1 048270, are incorporated herein by reference in their entirety, andparticular note is made of the flattened needle, which may be used withcertain exemplary embodiments of the medical lead disclosed herein.

The needle 200 comprises a body having a proximal end 204 and a distalend 206 and an inside lumen 208. The lumen 208 has an oblong crosssection. The oblong cross section of the lumen 208 is adapted to receivea stylet 202 (FIG. 30) and a paddle style lead 50. The cross section ofthe lumen 208 is such that the width is greater than the height. Atypical width for the lumen cavity to receive a paddle style lead 50 maybe 2.5 mm to 12 mm (0.1″ to 0.5″) with a height of 1.4 mm to 2.0 mm(0.055″ to 0.079″). The needle 200 may be made of stainless steel orother suitable materials. The needle 200 may also be adapted to insertmultiple wire leads. Advantageously, the present invention allows apaddle lead to be inserted percutaneously without requiring the lead 50to be rolled/contorted to fit the geometry of the needle lumen 208.

The needle 200 is further defined by an introducer portion (also 206) atthe body distal end 206. The introducer portion 206 has a top side and abottom side is shaped to allow for penetration of a patient's skin andother tissue. Typically, an epidural, Tuohy or modified Tuohy needle maybe used. The top side of the introducer portion 206 has an orifice toallow the paddle style lead 50 to exit the lumen 208 of the needle 200within the spinal column area after insertion of the needle 200. Theintroducer portion 206 may have the orifice at the distal endperpendicular to the lumen 208. A preferred exemplary embodiment of theneedle 200 has an introducer with a curvature. The curvature extendsfrom the bottom side of the introducer 206 to the top side of theintroducer to facilitate and guide the paddle style lead 50 duringinsertion. The radius of curvature for the introducer 206 may be, forexample, approximately 0.9″. Other curvatures may also be used.

FIG. 38 illustrates a perspective view of the stylet 202 having aproximal end that is adapted to mate with the needle hub. The stylet 202has a length nearly equivalent to the length of the body of the needle200. The stylet 202 has a distal tip shaped for matching with theorifice of the introducer of the needle 200. A handle end is affixed toa proximal end of the stylet 202. In the preferred embodiment, thestylet 202 fills the entire orifice of the introducer 206 to prevent anyskin or other tissue from entering the lumen 208 during insertion withinthe patient.

In at least one preferred exemplary embodiment, the stylet 202 may beconstructed of an elastomeric material, or deformable material that issufficiently flexible and resilient or redeformable to allow the stylet202 to be removed from the needle 200 even where the needle 200 has beensubjected to plastic deformation. Alternatively, the stylet 202 may beformed of stainless steel.

FIG. 39 illustrates a general flow diagram of an exemplary preferredmethod 300 of use or implantation of the implantable paddle-stylemedical lead 50. The method 300 generally follows these steps: makesmall incision 302; insert needle (with stylet) percutaneously throughincision into the epidural space 304; remove stylet from needle 306;insert guidewire through needle to assess epidural space 308; insertlead through needle with electrodes down 310; remove needle 312; andanchor paddle of lead to connective tissue, such as ligamentum flavum314.

Thus, exemplary embodiments of the paddle-style medical lead and methodare disclosed. One skilled in the art will appreciate that the presentinvention can be practiced with embodiments other than those disclosed.The disclosed embodiments are presented for purposes of illustration andnot limitation, and the present invention is limited only by the claimsthat follow.

1. A medical lead system comprising a medical lead for electricalstimulation or sensing, the medical lead comprising: a generally roundor tubular lead body having proximal and distal ends, and at least oneelectrical conductor extending between the proximal and distal ends; aconnector on the proximal end of the lead body in electricalcommunication with the electrical conductor; and a generally flat paddleon the distal end of the lead body having an electrode array comprisingat least one electrode in electrical communication with the electricalconductor, the paddle having proximal and distal ends and a lengthextending between the proximal and distal ends, the electrode arraybeing displaced along the length of the paddle toward the distal end,whereby the electrode array may be advanced into position for electricalstimulation or sensing with the flat paddle extending through connectivetissue, said connective tissue including ligamentum flavum, the flatpaddle having opposite major surfaces and electrode apertures in one ofthe major surfaces, and the electrode array comprises a plurality ofelectrodes exposed through electrode apertures; and an anchor adaptedfor clamping the flat paddle and anchoring the flat paddle to connectivetissue, the anchor comprising two clamping jaws adapted to clamp themajor surfaces of the flat paddle therebetween, at least one of theclamping jaws is provided with at least one rib adapted to engage theflat paddle and retain it in position.
 2. The medical lead system ofclaim 1 in which a plurality of ribs are provided on at least oneclamping jaw to engage the flat paddle and retain it in position.
 3. Themedical lead system of claim 2 in which the clamping jaws are separable,the clamping jaws being provided with mating knobs and cavities forattaching the clamping jaws together.
 4. The medical lead system ofclaim 1 in which the clamping jaws are pivotably connected to oneanother for movement between: a closed position for clamping the majorsurfaces of the paddle therebetween; and an open position in which theanchor may be moved relative to the paddle.
 5. A medical lead system forelectrical stimulation or sensing, the medical lead system comprising: amedical lead comprising: a generally round or tubular lead body havingproximal and distal ends, and at least one electrical conductorextending between the proximal and distal ends; a connector on theproximal end of the lead body in electrical communication with theelectrical conductor; and a generally flat paddle on the distal end ofthe lead body having an electrode array comprising at least oneelectrode in electrical communication with the electrical conductor, thepaddle having proximal and distal ends and a length extending betweenthe proximal and distal ends, the electrode array being displaced alongthe length of the paddle toward the distal end; an anchor configured forattachment to the paddle to anchor the paddle relative to biologicaltissue; and wherein the flat paddle has opposite major surfaces, and theanchor comprises two clamping jaws adapted to clamp the major surfacesof the flat paddle therebetween.
 6. The medical lead system of claim 5in which at least one of the clamping arms is provided with at least onerib adapted to engage the flat paddle and retain it in position.
 7. Themedical lead system of claim 5 in which a plurality of ribs are providedon at least one clamping arm to engage the flat paddle and retain it inposition.
 8. The medical lead system of claim 7 in which the clampingarms are separable, the clamping arms being provided with mating knobsand cavities for attaching the clamping arms together.
 9. The medicallead system of claim 5 in which the clamping jaws are pivotablyconnected to one another for movement between: a closed position forclamping the major surfaces of the paddle therebetween; and an openposition in which the anchor may be moved relative to the paddle.
 10. Amedical lead system comprising: a medical lead for electricalstimulation or sensing, the medical lead comprising: a generally roundor tubular lead body having proximal and distal ends, and at least oneelectrical conductor extending between the proximal and distal ends; aconnector on the proximal end of the lead body in electricalcommunication with the electrical conductor; a generally flat paddle onthe distal end of the lead body having an electrode array comprising atleast one electrode in electrical communication with the electricalconductor, the paddle having proximal and distal ends and a lengthextending between the proximal and distal ends, the electrode arraybeing offset along the length of the paddle toward the distal end suchthat the portion of the flat paddle proximal of the electrode array hasa length of at least 1½ inches, whereby the electrode array may beadvanced into position for electrical stimulation or sensing with theportion of the flat paddle proximal of the electrode array extendingthrough connective tissue, said connective tissue including theligamentum flavum; wherein the flat paddle has opposite major surfacesand electrode apertures in one of the major surfaces, and the electrodearray comprises a plurality of electrodes exposed through electrodeapertures: and an anchor adapted for clamping the flat paddle andanchoring it to connective tissue, wherein the anchor comprises twoclamping jaws adapted to clamp the major surfaces of the flat paddletherebetween.
 11. The medical lead system of claim 10 in which theclamping jaws are pivotably connected to one another for movementbetween: a closed position for clamping the major surfaces of the paddletherebetween; and an open position in which the anchor may be movedrelative to the paddle.